Engineering Commons^™

Label-Free Mapping Of Near-Field Transport Properties Of Micro/Nano-Fluidic Phenomena Using Surface Plasmon Resonance (Spr) Reflectance Imaging, Iltai Kim

Doctoral Dissertations

My doctoral research has focused on the development of surface plasmon resonance (SPR) reflectance imaging technique to detect near-field transport properties such as concentration, temperature, and salinity in micro/nano fluidic phenomena in label-free, real-time, and full-field manner. A label-free visualization technique based on surface plasmon resonance (SPR) reflectance sensing is presented for real-time and full-field mapping of microscale concentration and temperature fields. The key idea is that the SPR reflectance sensitivity varies with the refractive index of the near-wall region of the test mixture fluid. The Fresnel equation, based on Kretschmann’s theory, correlates the SPR reflectance with the refractive index …

Production Of Nanocrystalline Rdx By Ress : Development And Material Characterization, Victor Stepanov

Dissertations

The aim of the present work was to address the hazardous vulnerability of energetic materials to accidental initiation. An improved form of the explosive RDX with a significantly reduced sensitivity to stimuli including shock and impact was sought. The direction of this research was to investigate the effect of RDX crystal size reduction down to nano-scale dimensions on the sensitivity characteristics. Although size reduction of energetic crystals has been demonstrated often to result in a sensitivity reduction, the effect at the nano-scale particle size has not been investigated.

To generate nanocrystalline RDX a recrystallization process was developed based on rapid …

An Ultrahigh Vacuum Complementary Metal Oxide Silicon Compatible Nonlithographic System To Fabricate Nanoparticle-Based Devices, Arghya Banerjee, Biswajit Das

Electrical & Computer Engineering Faculty Research

Nanoparticles of metals and semiconductors are promising for the implementation of a variety of photonic and electronic devices with superior performances and new functionalities. However, their successful implementation has been limited due to the lack of appropriate fabrication processes that are suitable for volume manufacturing. The current techniques for the fabrication of nanoparticles either are solution based, thus requiring complex surface passivation, or have severe constraints over the choice of particle size and material. We have developed an ultrahigh vacuum system for the implementation of a complex nanosystem that is flexible and compatible with the silicon integrated circuit process, thus …

Mixing Of Nanoparticles In A Stirred Tank In High Pressure Carbon Dioxide, Nitin Aggarwal

Theses

Mixing of nanoparticles of different compositions offers wide opportunities in manufacturing new nanocomposite materials with unique electronic, optical, mechanical, and chemical properties. However, due to large cohesive forces between nanoparticles, they often form large micron-sized agglomerates, thus losing their main advantage of small size and high surface area. Therefore, breaking of these agglomerates is necessary prior to mixing. One of the techniques to achieve deagglomeration and mixing of nanoparticles is based on rapid depressurization/expansion of supercritical suspensions. where the suspension of initially premixed agglomerates in supercritical CO₂ pass through the nozzle undergoing deagglomeration as a result of rapid expansion …

Magnetically Assisted Impaction Mixing Of Nanosize Particles, James V. Scicolone

Theses

Magnetically assisted impaction mixing (MAIM) is a novel dry mixing technique, which can be used to mix nanoparticles. Mixing of nanoparticles is usually conducted in solvent-based mixing techniques. The solvents used in these techniques are usually organic, which can be expensive and harmful to the environment. MAIM creates homogeneous nanoparticle mixtures while eliminating conditioning and drying steps associated with wet mixing techniques. To create the best mixing quality of nanoparticles, MAIM was optimized by studying the effects of magnet-to-sample ratio, time, magnet size, and constituents of the mixture. The results were then compared with other well-known mixing techniques.

To characterize …

Probing And Tuning The Size, Morphology, Chemistry And Structure Of Nanoscale Cerium Oxide, Satyanarayana Kuchibhatla

Electronic Theses and Dissertations

Cerium oxide (ceria)-based materials in the nanoscale regime are of significant fundamental and technological interest. Nanoceria in pure and doped forms has current and potential use in solid oxide fuel cells, catalysis, UV- screening, chemical mechanical planarization, oxygen sensors, and bio-medical applications. The characteristic feature of Ce to switch between the +3 and + 4 oxidation states renders oxygen buffering capability to ceria. The ease of this transformation was expected to be enhanced in the nanoceria. In most the practical scenarios, it is necessary to have a stable suspension of ceria nanoparticles (CNPs) over longer periods of time. However, the …

Process For Formation Of Cationic Poly (Lactic-Co-Glycolic Acid) Nanoparticles Using Static Mixers, Yamuna Reddy Charabudla

University of Kentucky Master's Theses

Nanoparticles have received special attention over past few years as potential drug carriers for proteins/peptides and genes. Biodegradable polymeric poly (lactic-co-glycolic acid) (PLGA) nanoparticles are being employed as non-viral gene delivery systems for DNA. This work demonstrates a scalable technology for synthesis of nanoparticles capable of gene delivery. Cationic PLGA nanoparticles are produced by emulsiondiffusion- evaporation technique employing polyvinyl alcohol (PVA) as stabilizer and chitosan chloride for surface modification. A sonicator is used for the emulsion step and a static mixer is used for dilution in the diffusion step of the synthesis. A static mixer is considered ideal for the …

High Performance Zno Varistors Prepared From Nanocrystalline Precursors For Miniaturised Electronic Devices, Suresh Pillai, Declan Mccormack, John Kelly, Raghavendra Ramesh

Articles

An industrially viable solution-based processing route using minimal amounts of solvent has been used to prepare bulk quantity nanopowders (average particle size 15.3 nm) for the fabrication of ZnO varistors. The xerogels, calcined powders and sintered materials were fully characterised. The preparation of varistors from nanopowders has been optimised by studying the effect of temperature on grain growth, densification and breakdown voltage. The varistors are prepared by sintering at 1050 C for 2 hours, a temperature that is significantly lower than that used in the current industrial process. Highly dense varistor discs prepared from the sintered material produce devices, with …

Electrochemistry Of Liv3o8 Nanoparticles Made By Flame Spray Pyrolysis, T J. Patey, See How Ng, R Buchel, N Tran, F Krumeich, Jiazhao Wang, Hua-Kun Liu, P Novak

Faculty of Engineering - Papers (Archive)

LiV₃O₈ nanoparticles (primary particles with ca. 50 nm diameter) have been synthesized by flame spray pyrolysis (FSP). The powder was characterised by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and galvanostatic cycling. The initial discharge capacity of the LiV₃O₈ nanoparticles is 271 mAh g^-1 when discharged from its open-circuit potential to 2.0 V vs Li/Li⁺ at a specific current of 100 mA g^-1 under ambient conditions. The nanoparticles retained a specific discharge capacity of 180 mAh g^-1 beyond 50 cycles. This paper describes the synthesis route as well as …

A New Method Of Synthesizing Black Birnessite Nanoparticles: From Brown To Black Birnessite With Nanostructures, Shizhi Qian, Marcos A. Cheney, Pradip K. Bhowmik, Sang W. Joo, Wensheng Hou, Joseph M. Okoh

Mechanical Engineering Faculty Research

A new method for preparing black birnessite nanoparticles is introduced. The initial synthesis process resembles the classical McKenzie method of preparing brown birnessite except for slower cooling and closing the system from the ambient air. Subsequent process, including wet-aging at 7◦C for 48 hours, overnight freezing, and lyophilization, is shown to convert the brown birnessite into black birnessite with complex nanomorphology with folded sheets and spirals. Characterization of the product is performed by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), thermogravimetric analysis (TGA), and N2 adsorption (BET) techniques. Wet-aging and lyophilization times are shown to …